Effects of Stimulus Onset Asynchrony on the Dichotic Listening Performance of Persian-Speaking Older Adults with Normal Hearing Compared to Younger Peers

Abstract

Background and Aim: Aging leads to noticeable functional changes in central auditory processing and dichotic function. This study aims to compare the dichotic listening function between Persian-speaking younger and older adults under different Stimulus Onset Asynchrony (SOA) conditions.

Methods: Persian syllables were presented dichotically to the participants including 20 normal-hearing younger adults (aged 18-29 years) and 20 normal-hearing older adults (aged 60-75 years). The onset time of the concurrent stimuli differed from 0 to 150 ms between the right and left ear. The effects of SOA changes (0, 30, 60, 90, and 150 ms) on dichotic listening function were investigated. The percentage of Binaural Ear Correct (BEC%), as an indicative of dichotic performance, was measured.

Results: The BEC% scores decreased with the decrees of SOA values in both groups. However, this decline was more pronounced and significant in the elderly group. In contrast, younger adults achieved higher BEC% scores in all SOA values compared to older adults.

Conclusion: The reduced BEC% in older adults (particularly at lower SOA levels) indicate  Department of Audiology, School of Rehabilitation, Shahid Beheshti aging on central auditory processing and dichotic function. The results can be useful in University of Medical Sciences, designing and improving rehabilitation programs for older people.